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Minimum Induced Drag of Non-Planar Ground Effect Wings with Small Tip Clearance

Published online by Cambridge University Press:  07 June 2016

T Kida  and
Y Miyai
T Kida
Affiliation:
University of Osaka Prefecture, Japan
Y Miyai
Affiliation:
University of Osaka Prefecture, Japan
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Summary

This paper treats theoretically the problem of the minimum induced drag of non-planar ground effect wings with both tips very close to the ground, within the limitations of the linearised lifting-line theory. The gap clearance between the wing tip and the ground is assumed to be very small and, using this small parameter, an approximate theory, which yields the minimum induced drag of a non-planar ground effect wing, is formulated by the method of matched asymptotic expansions. As a check on the accuracy of the method, this theory is compared with the exact theory for a semicircular wing. This shows that the present method is accurate within the small gap clearance. Moreover, the present method is applied to other wing configurations, such as semi-elliptic wings and wings with endplates, circular arc wings in a tube and circular arc wings. These computations show the theory to be very effective and it can be easily extended to various spanwise cambers.

Type
Research Article
Information
Aeronautical Quarterly , Volume 25 , Issue 1 , February 1974 , pp. 19 - 36
Copyright
Copyright © Royal Aeronautical Society. 1974

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References

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